Items

• rocket

  A jet engine that operates on the same principle as the firework rocket, consists essentially of a combustion chamber and an exhaust nozzle, carries either liquid or solid propellants which provide the fuel and oxygen needed for combustion and thus make the engine independent of the oxygen of the air, and is used especially for the propulsion of a missile (such as a bomb or shell) or a vehicle (such as an airplane)
• rod

  A slender bar (as of wood or metal)
• root

  A number that reduces an equation to an identity when it is substituted for one variable
• rotational

  The action or process of rotating on or as if on an axis or center
• satellite

  A celestial body orbiting another of larger size
• scalar

  A quantity (such as mass or time) that has a magnitude describable by a real number and no direction
• science

  Such knowledge or such a system of knowledge concerned with the physical world and its phenomena
• screen

  A flat surface on which a picture or series of pictures is projected or reflected
• secant

  A straight line cutting a curve at two or more points
• second

  The 60th part of a minute of angular measure.
• second

  Next to the first in value, excellence, or degree.
• semiconductor

  Any of a class of solids (such as germanium or silicon) whose electrical conductivity is between that of a conductor and that of an insulator in being nearly as great as that of a metal at high temperatures and nearly absent at low temperatures
• sequence

  A continuous or connected series
• series

  An arrangement of the parts of or elements in an electric circuit whereby the whole current passes through each part or element without branching
• set

  A number of things of the same kind that belong or are used together; A number of things of the same kind that belong or are used together
• shape

  The visible makeup characteristic of a particular item or kind of item
• shear

  An action or stress resulting from applied forces that causes or tends to cause two contiguous parts of a body to slide relatively to each other in a direction parallel to their plane of contact
• sheet

  A wide space or area
• shell

  Something that encloses another thing especially to protect it
• sign

  A movement of the body or limbs that expresses or emphasizes an idea or feeling
• significant

  Having great meaning or lasting effect
• simple

  Free from all additions or embellishment
• slit

  A long deep cut
• solenoid

  Coil of wire usually in cylindrical form that when carrying a current acts like a magnet so that a movable core is drawn into the coil when a current flows and that is used especially as a switch or control for a mechanical device (such as a valve).
• solid

  Possessing or characterized by the properties of a solid : neither gaseous nor liquid.